Preselecting mechanism



March 18, 1947.

A. c. TEN CATE ETAL PRESELECTING MECHANISM Filed May 29, 1945 3 Sheets-Sheet l INVENTORS Z72%z(7' Cienaze Mal/ am C. .191??? 5% 69% J: Kim

.izfarney A. C. TEN CATE ET AL PRESELECTING MECHANISM Filed May 29, 1945 mmkwww /Z March 18, 1947.

J VVEJVTORS. .ir/ur C 1%??66212 William C. JyereZ/ QM L K izforney March 18, 1947.

A. C. TEN CATE ETAL PRESELECTING MECHANISM Filed May 29, 1945 3 Sheets-Sheet 3 w? m Mr? M E 6 r V 9 I w.

Jirlzzr C Ten Mil/[am QC. (/5 5 69M Q mm Patented Mar. 18, 1947 UNITED STATES PATENT OFFICE PRESELECTING MECHANISDI Application May 29, 1945, Serial No. 596,482

Claims.

This invention relates to a preselecting mechanism and is an improvement upon the invention disclosed in Patent 2,293,299, granted August 18. 1942. In this patent, there is disclosed a motor driven preselecting mechanism wherein oppositely driven movements are provided between a source of power, such as a motor, and a device to be indexed, such as a condenser. The oppositely driven movements locate the final index position by applying equal and opposite indexing forces. At the time when such forces are equal and opposite, the source of power, such as the motor, functions merely as a torque source. In the case of a motor, continued rotation is no longer possible, since stalling is the normal condition after indexing.

Inasmuch as the actual indexing occurs intermittently, it is customary to provide a motor which is overloaded for a short period of time during preselection. As a rule and depending upon the frequency of preselection, overloads of the order of 1000% and more may be imposed upon the motor. By virtue of this, small size and light motors may be used.

It is clear, therefore, that motors operating under such conditions of overload should be energized only during preselection and promptly deenergized upon the end of a preselecting cycle. The invention hereinafter described provides a simple and effective means whereby the stalling of the motor is utilized for deenergizing the motor circuit.

In order to explain the invention more fully, reference will now be made to the drawings wherein Figure 1 is a side elevation of a mechanical system embodying the invention. Figure 2 is an end view on 22 of Figure 1. Figure 3 is an enlarged detail showing two preselector units. Figure 4 is a section on 4-4 of Figure 3. Figure 5 is a section on 55 of Figure 4. Figure 6 is a sectional detail on 66 of Figure 1, and Figure 7 is an exploded view, partly diagrammatic, illustrating one preselector unit and showing the motor and electrical circuit.

End plates I0 and II may have spacer rods I2 (only one is visible in Figure 1) and angle iron I3 to form a skeleton frame work for supporting the entire mechanism. Rods I2 may be maintained in position by having threaded ends passing through suitable apertures in end plates I0 and I I and having nuts I4 retain the assembly rigidly in position. Angle iron I3 may be rigidly joined to end plates I0 and II in any suitable fashion.

End plate I I has off-set portion I'I carrying mo- Lil tor supporting plate I8. Motor supporting plate I8 may be secured to off-set II in any desired fashion, such as by bolts 20. Motor supporting plate I8 supports end plate 22 in resilient mounting 23. Mounting 23 may consist of a bolt and rubber or other flexible washer for supporting plate 22 on plate 23 in a vibration-free manner.

End plate 22 cooperates with end plate II! for s p orting a load having shaft 25 to be turned to any one of a number of preselected angular positions. Shaft 25 may carry any desired device to be turned and, as shown here, forms a shaft of a variable condenser group. Thus, shaft 25 may carry condenser rotor 26 interleaved with stator 21 carried by frame rods 28 rigidly secured between plates I0 and 22. It is clear that the vibration-free mounting b which end plate 22 is supported is required only because the load happens to be a variable condenser. If described, the vibration-free mounting may .be omitted.

Load shaft 25 may be journaled in plates I0 and 22 in any suitable fashion. Thus, plate I0 may have journal 29 rigidly supported thereby and in which shaft 25 may turn. Plate 22 may have journal 30 formed therein for supporting the other end of shaft 25. Journal 30 is preferably of the type havin means for adjusting the end play on shaft 25 and also for applying any desired amount of friction. Inasmuch as journals 29 and 30 are of the usual type used in such devices, no detailed description thereof is deemed necessary.

Load shaft 25 carries gears 32 rigidl locked thereon for driving purposes. Gears 32 are two separate similar gears having a spring connection tending to eliminate backlash. This type of gear is well known in the art and is used quite frequently in condenser drives for precision.

Load gear 32 meshes with gear 33 on preselecting shaft 34. Preselecting shaft 34 has its angu lar position preselected by the mechanism and, by virtue of its position, serves to adjust load shaft 25 to the final preselected position. 34 may be combined with shaft 25 if desired, and the load applied directly to shaft 34. For purposes of compactness, however, it is preferred to separate preselecting shaft 34 and load shaft 25 and have a drive between them.

Preselecting shaft 34 is journaled in end plates ID and II. This shaft carries a plurality of units which, together with remaining apparatus, constitute a plurality of preselector units. Inasmuch as the units are similar, one complete unit shown in exploded form in Figure '7 will be described in detail.

Shaft 34 has a pair of oppositely disposed flats 35 and 38 ground or formed thereon and extending throughout its effective length. At the center of each preselector section is washer 38 rotatively mounted on shaft 34. Washer 38 is provided with aperture 39 just clearing the normal uncut circular section of shaft 34. on opposite sides of washer 38 are clamping sleeves 48 and 4| having bores 42 shaped to correspond with the mutilated section of shaft 34. Thus, sleeves 40 and 4| may slide longitudinally of the shaft but are rotatably locked. Each sleeve has an end flange 43. For precision in preselection, it is necessary that sleeves 40 and 4| be accurately shaped so that no rotary movement with respect to shaft 34 is possible. By forcing sleeves 40 and 4| against the opposite sides of washer 38, it is possible to lock washer 38 in any desired rotary position with respect to shaft 34.

Washer 38 is provided with finger 44 against which the driving movements exert the forces necessary for operation of the device. In order to increase the angular range of operation of the device, a plurality of rings 45 to 48 inclusive may be provided. As shown here, four rings are provided. The number, however, may be increased or decreased as the case may be. Rings 45 to 48 inclusive have apertures 49 sufficiently large to ride on the outside of sleeve 48. Each of the rings is provided with driving finger 59 having tip bent out of the plane of the driving ring. When the driving rings are disposed adjacent each other, each tip 5| overlies the adjacent ring toward center washer 38. Thus, each driving ring may make almost a complete turn freely and then serves to drive the next succeeding ring. Driving ring 45 has its finger 58 adapted to engage finger 44 of washer 38 to drive shaft 34.

Centerwasher 38 has driving rings 53 to 58 inclusive on the other side (the right-hand side as seen in Figure 7) with each driving'ring being provided with finger 51. These driving rings are similar to driving rings 45 to 48 with fingers 55 pointing toward washer 38. Driving rings 53 to 55 inclusive are mounted on sleeve 4| to rotate thereon.

It is clear that, if each group of driving rings is driven at equal and opposite speeds, center washer 38 will be moved to a certain position. This certain position will be reached when finger 44 of washer 38 is urged equally and in opposite direction by the fingers of driving rings 45 and 53. The exact position of shaft 34 may be determined by relative adjustment of the shaft and washer 38.

Driving rings 45 to 48 inclusive and 53 to 58 inclusive cooperate with driving gears 88 and 8| respectively. These gears are provided with finger 62 and 83 extending laterally toward center washer 38. Rings 45 to 48 inclusive and gear 80 are rotatably disposed upon clamping sleeve 48 with flange 43 retaining the assembly thereon. Similarly, rings 53 to 55 inclusive and gear 5| are rotatably disposed upon clamping sleeve 4| with flange 43 thereof retaining that assembly thereon. Between adjacent preselector units,'as shown in Figures 3 and 4 for example, spacing washers 55 may be disposed between opposed end flanges 43 and 43 of the clamping sleeves.

The complete system of sleeves and spacer washers 65 may be disposed between fixed collar 56 pinned or rigidly fastened to shaft 34 and a means for exerting an end thrust at the other end of the shaft. This means may include sleeve 61 rotatably mounted in end plate said sleeve having flange 68 for preventing loss of sleeve 81.

Sleeve 61 may have spacing member 69 extending to threaded portion 19 of shaft 34 with nuts 1| disposed over said threaded portion. By adjusting nuts ll, pressure on sleeve 61 along the shaft may be either exerted or relaxed. Thus central washers 38 may be tightened in predetermined position. A desirable means for controlling the pressure along the shaft against the various sleeve assemblies is disclosed and claimed in Patent 2,179,748. The washer assembly for a preselector unit is disclosed and claimed in Patent 2,161,183.

Gear 60 of each preselector section meshes with pinion I2 freely rotatable upon rod 13 rigidly disposed between end plates l8 and II. Each pinion 12 has reduced portion 14 for clearing gear 5|. The various pinions 12 are so proportioned in length as to prevent excessive end play along rod 13. Otherwise, their adjustment is not critical.

Gear 6| meshes with pinion l5 freely rotatable on rod 18 rigidly mounted between end plates l8 and H. Pinions 15 have reduced portion 11 for clearing gears 88 and are mates to pinions 12.

As is clearly evident in Figure 4, a pair of pinions I2 and 15 for one preselector unit are displaced axially, the pinions themselves being wide enough and rods 13 and 18 being so disposed as to cause these two to mesh with each other. Each preselector section has one movable pinion '59 which is adapted to simultaneously engage drive gear 88 and one of gears 12 or 15, in this particular instance gear 15. Pinion 19 is carried on armature bracket 8| rotatably mounted on rod 16 between adjacent pinions l5. Armature bracket 8| has armature portion 82. Bracket 8| i normally biased downwardly as seen in Figure 7 by spring 83 so that pinion I9 is normally out of engagement with drive gear 88. The body of bracket 8| may have wing portion 84 cooperating with rod 85 disposed between end plates, Ill and II and serving to limit the movement of said bracket for engaging pinion 19 and drive gear 89.

Drive gear 88 extends the entire distance between end plates IO and II and has shaft portions 85 journaled in end plates I8 and H for rotatably supporting the gear. Drive gear 88 may be driven through gear 81 carried on one of the shaft portions, in this instance just beyond mounting plate I I, and meshes with pinion 88. Pinion 88 is rigidly connected to gear 89, the two being concentric and rotatably mounted upon shaft 90. It is understood that pinion 88 and gear 89 operate as a unit but may freely rotate on motor shaft 99.

Gear 89, in turn, meshes with pinion 9| carried by jackshaft 92 journaled in motor end plates 93 and 94. Jackshaft 92 carriers gear 95 at the end adjacent plate 94 and this gear. Gear 95 is connected to shaft 92 through coil spring 98, one end of coil spring 98 being locked to gear 95, while the other end is locked towasher 91 rigidly mounted upon shaft 92. Thus, gear 95 has a spring connection to shaft 92 permitting limited relative rotary movement therebetween.

Gear 95 meshes with pinion I mounted upon shaft 90. Shaft 98 forms part of motor I82 having end plates 93 and 94.

Rigidly carried from mounting plate l8 is a generally U shaped frame I84 having suitable clearances I through which jackshaft'92 may project. and H11, these contacts being normally open but being adapted to be closed by finger I08 carried Frame I04 carries switch contacts "18 by jackshaft 92 and adapted to be moved upwardly, as seen in Figure '7, upon movement of said jackshaft.

As has been pointed out before, each preselector section has movable gear 79 mounted upon rotatable armature bracket 8|. In order to move gear 19 into meshing engagement with drive gear 80, each preselector unit is provided with electromagnet III; having pole piece III adapted to cooperate with armature portion 82. The series of electromagnets may be bolted on angle iron I3 as shown, this angle iron providing a desirable magnetic circuit for each electromagnet. Each electromagnet H8 is connected by wires III and H2 to terminals I I3 and H4 respectively. Wire H2 may have switch H5 therein, this switch being one of a bank of switches, one for each preselector. Switch H5 may be any type desired, either manual or automatic Switch contact I! is connected by lead H to movable contact II 1 of relay I I8. Movable contact H1 is normally biased against fixed contact I I8 connected through terminal I53 and lead I20 to motor I02. Motor IllZ has its other terminal connected by lead I2! to terminal H 1. Relay H8 has two windings having one connection in common at lead I22 and going down to terminal H 2. One winding of relay HI} is connected to off-normal relay contact I23, while the other winding is connected by lead I24 to switch contact I06. A source of power, suchas transformer secondary I26, is connected between leads H6 and I22 through switch I21, mechanically tied to switch I I5 to open and close together.

In the normal running position of the motor, spring blade MI is stiff enough and the load on the gear drive is light enough so that finger I08 may contact spring blade I01 but is prevented from closing the switch. Thus, gravity or spring blade Ill! may be considered as biasing the stator under normal running conditions to one end position. When the motor stalls, due to the m chanism reaching home position, the load becomes so great and the reaction between gears becomes suflicient to move the stator from its bias position to a position where switch contacts H36 and I0! are closed.

The relay, motor and electromagnet may be operated either by direct or alternating current.

Relay H8 has its two windings so disposed as to aid each other, as shown by the arrows.

The operation of the electrical portion of the system is as follows. Assume that switches H5 and I2! are close Electromagnet H0 will thereupon be energized, and draw up movable pinion I9 into engagement with drive gear 80. At the same time, motor I02 will be energized through the normal position of relay H8, as shown in Figure 7. When a preselection point has been reached by the mechanism, motor I02 will stall.

The reaction to stalling will cause end plates 93 and 9-4 to move upwardly, as seen in Figure 7, it being understood that the motor normally rotates its shaft in a counter-clockwise direction, as seen in Figure 7. The clockwise movement of the motor frame, due to the stalling and consequent movement of end plates 93 and 94', will move jackshaft 92 upwardly around the motor shaft, as seen in Figure '7. Since this shaft is parallel to the motor shaft and by virtue of the gear relationships, the motor drive will not be disturbed. However, the reaction of the motor frame will result in switch contacts IE6 and I01 closing. The closure of these two contacts completes a circuit through the left winding of relay H8 and results in movable contact HI being drawn up against fixed contact I23. In this position, the right winding of relay I I8 has its circuit completed, so that relay H8 will hold movable contact II'! in position independently of the other winding. When movable contact H1 is drawn against fixed contact I23, the power circuit to motor I02 is broken. When this occurs, the motor assumes its normal position, its return being facilitated by the spring of contact IIiI. Other means of biasing the motor frame may be provided, however. At the same time, the circuit through electromagnet H8 is also interrupted so that this will not overheat. The only circuit remaining will be through right winding of relay H3, and this will remain energized so long as switches H5 and I2? are closed. This relay may be designed for continuous duty as a safety precaution.

It will be evident from Figures 1, 2 and 7 that the motor shaft has a step-down gear ratio to jackshaft 92, and this. in. turn, has a further stop-down ratio to gear By virtue of this gear step-down ratio, the torque available for swinging the motor frame when the motor stalls is greatly increased. This is particularly important in that power requirements for the motor thus become reduced. In practice, has been found that a low power motor may be used, the power developed therefrom being sufficient to drive the preselector mechanism and, at the same time, to accomplish motor frame movement.

It is understood that the preselector units in Patent 2,2932% may be used instead of the multi-washer assembly as shown in Figure 7. Since the stalling effect of the motor is desired, the precise details of the preselector may vary.

What is claimed is:

l. A preselector comprising a member having a predetermined range of movement and adapted to be indexed to a preselected position in said range, lost motion means adapted to move at equal speeds in opposite directions for moving said member, an electric motor for driving said two means, said motor having a stator and rotor and being adapted to stall when said member has reached a preselected position whereupon said two means will exert equal opposing forces on said member, a speed reducing gear drive from said motor rotor to said two means, said gear drive including a jackshaft parallel to said motor shaft with said jackshaft being geared down, means for supporting said jackshaft from the stator of said motor, means for mounting said stator so that it has limited rotary movement, means for biasing said stator to one end position, a control circuit for said motor, said circuit including a switch, and means for coupling said switch to said stator whereby when said motor stalls reaction causes said stator to move through a limited are away from its biased position and operate said switch to open said motor circuit.

2. The system of claim 1 wherein said member is rotatable with the range of movement being angular.

3. A preselector comprising a rotary member having a predetermined range of angular movement and adaptec to be indexed to a preselected angular position in said range, lost motion means adapted to rotate at equal speeds in opposite directions for rotating said member, an electric motor having a stator and rotor for driving said two means, said motor being adapted to stall when said member has reached its preselected position whereupon said two means will exert equal opposing forces on said member, a speed reducing gear drive from said motor rotor to said two means, said gear drive including a jackshaft laterally displaced from and parallel to said rotor axis and geared down, means for supporting said jackshaft from the stator of said motor, means for mounting said stator so that it has limited rotary movement around the rotor, means for biasing said stator to one end position, a supply circuit for said motor, said circuit including a switch, and means for coupling said switch to said stator whereby when said motor stalls reaction causes said stator to move away from its biased position through a limited are and. operate said switch to open the motor circuit, said rotor having a step-up gear ratio to said jackshaft permitting a motor of low power to be used.

4. The structure of claim 3 wherein said jackshaft has gears adjacent both motor ends, and wherein gears meshing with said jackshaft gears are coaxial with said motor. I

5. A preselector comprising a rotary member having a predetermined range of angular movement and adapted to be indexed to a preselected angular position in said range, lost motion means adapted to rotate at equal speeds in opposite directions for rotating said member, an electric motor having a stator and rotor for driving said two means, a speed reducing gear train between said motor and said two means, said train including one gear movable in and out of meshing engagement to connect said motor and lost motion means, said motor being adapted to stall when said member has reached its preselected position whereupon said two means will exert equal opposing forces on said member, said gear train including a jackshaft laterally displaced from and parallel to said rotor axis and geared down with respect to said rotor axis, means for supporting said jackshaft from the stator of said motor, means for mounting said stator so that it has limited rotary movement around the rotor, means for biasing said stator to one end position, electromagnetic means for controlling said movable gear, said movable gear being normally out of REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,161,183 Mastney June 6, 1939 2,246,050 Leishman June 17, 1941 

